Retired boxer Floyd Mayweather Jr. has fuelled speculation he is eyeing a one-off UFC match, shown stepping into the Octagon in a now viral video.

Mayweather posted a video of himself strutting into the mixed martial arts promotion's infamous Octagon, prompting talk of a re-match with Conor McGregor.

Mayweather also posted photos to social media of his bout with McGregor and the $USD100 million fight cheque he received to come out of retirement for the exhibition match, where he successfully took his professional record to 50-0 with a 10th-round TKO.

The UFC two-division 'champ-champ' took the bait hook, line and sinker, responding on social media with a picture of himself and his son with the caption 'F--- the Mayweathers'.

Mayweather is set to turn 41 next month and was meant to be officially retired (again), however since his bout against McGregor in August last year, he has teased MMA and boxing fans about a possible rematch in the Irishman's arena and was at one point in talks with the UFC on a deal, according to UFC president Dana White.

White has said he wants McGregor back fighting in the Octagon, but not like this. McGregor hasn't fought in MMA since UFC 205 when he defeated Eddie Alvarez to make history as the first person to be a current two-division UFC champion.

Since then the 29-year-old has been under pressure to defend his titles, or risk being stripped of them.